This invention relates to industrial gratings, typically used in floor construction to provide covering for drain and cleaning channels, in animal production, food processing and other floor constructions. The grating constructions of this invention may also be used to support gas-liquid and solid-gas or solid-liquid contact media, e.g., scrubber saddles, rings and the like, in chemical process equipment. More particularly, this invention relates to an improvement in polyester bonded glassfiber gratings and to a method of manufacture and assembly.
It is common practice in industrial establishments to provide drain and cleaning channels in floors which permit scrubbing and cleaning of the floors and collection of cleaning solutions and spilled industrial solutions into an open drain channel. These drain channels are typically covered with a steel grating. The gratings, typically, are in a grid configuration. This type of construction permits the maintenance of clean working and processing conditions, easy access to drainage channels and, in general, an improved working area. Steel gratings are, of course, heavy and difficult to handle. Additionally, they are subject to corrosion by repetitive contact with water and air and by virtually all processing solutions. Steel gratings are, of course, electrically conductive, and in some environments present electrical shock hazerds. Steel gratings are also cold and have limited flexibility and generally do not provide a pleasant walking surface. All of these and other disadvantages of steel gratings have been long recognized. Nevertheless, steel gratings are still in common use and a fully satisfactory alternative has not generally been available.
Various attempts have been made to provide plastic coated gratings or plastic gratings. For example, one approach is to lay alternating layers of fiberglass roving in a recess form and to pourcast polyester bonding resin over the fibers. Sometimes abrasive particles are bonded to the grating or may be included in the original casting of the grating in the obvious manner by placing the abrasive particles in the bottom of the form and then casting the resin over the fibers and the particles. This process produces only a marginally satisfactory product and is infected with a number of serious disadvantages. For example, gratings of this type have no drainage channel if the grating is laid flat on a floor, as is frequently the case in, for example, food processing plants. Additionally, the area of intersection of the portions of the gratings is an area of weakness because of the disruption of the fiber resin bonding and the asymmetrical disposition of the resins in this area. Gratings constructed according to this method are unnecessarily bulky and heavy and like the earlier devices, do not permit drainage.
Additionally, many of these gratings involve a complicated and time-consuming method of assembly and attachment of the various components to each other.
An improvement to the industrial grating has been disclosed in Wiechowski, et al., U.S. Pat. No. 4,244,768, wherein glass fiber grating components are manufactured utilizing pultrusion techniques, the main parallel grating elements being connected by round dowels running perpendicular to, and through, the main grating elements. Wiechowski, et al., also discloses individual grating elements spaced between and perpendicular to the main grating elements disposed in a slot formed in the connecting dowel.
Typically, the prior art must be held in the desired configuration while the various components are fastened or bonded together. This process requires the construction and use of forms or specialized equipment that are expensive and space-consuming. Further, the number of gratings that may be assembled at any given time is limited by the number of forms available and the space available to store the individual gratings in their respective forms while the bonding material cures properly. U.S. Pat. Nos. 469,519 and 469,520 disclose key-bar locking mechanisms for holding the grating elements apart, but does not provide the additional grating surfaces or increased overall composite integrity of the grating.
These and other disadvantages are overcome according to this invention by the construction of a light-weight, high strength grating using the principles taught hereinafter.